/**
 *    Copyright ${license.git.copyrightYears} the original author or authors.
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */
package org.mybatis.generator.plugins;

import static org.mybatis.generator.internal.util.StringUtility.isTrue;

import static org.mybatis.generator.internal.util.JavaBeansUtil.getGetterMethodName;

import java.util.Iterator;
import java.util.List;
import java.util.Properties;

import org.mybatis.generator.api.PluginAdapter;
import org.mybatis.generator.api.IntrospectedColumn;
import org.mybatis.generator.api.IntrospectedTable;
import org.mybatis.generator.api.dom.OutputUtilities;
import org.mybatis.generator.api.dom.java.FullyQualifiedJavaType;
import org.mybatis.generator.api.dom.java.JavaVisibility;
import org.mybatis.generator.api.dom.java.Method;
import org.mybatis.generator.api.dom.java.Parameter;
import org.mybatis.generator.api.dom.java.TopLevelClass;

/**
 * This plugin adds equals() and hashCode() methods to the generated model classes. It demonstrates the process of
 * adding methods to generated classes
 * <p>
 * The <tt>equals</tt> method generated by this class is correct in most cases, but will probably NOT be correct if you
 * have specified a rootClass - because our equals method only checks the fields it knows about.
 * <p>
 * Similarly, the <tt>hashCode</tt> method generated by this class only relies on fields it knows about. Anything you
 * add, or fields in a super class will not be factored into the hash code.
 * 
 * @author Jeff Butler
 * 
 */
public class EqualsHashCodePlugin extends PluginAdapter {

  private boolean useEqualsHashCodeFromRoot;

  @Override
  public void setProperties(Properties properties) {
    super.setProperties(properties);
    useEqualsHashCodeFromRoot = isTrue(properties.getProperty("useEqualsHashCodeFromRoot"));
  }

  /**
   * This plugin is always valid - no properties are required
   */
  public boolean validate(List<String> warnings) {
    return true;
  }

  @Override
  public boolean modelBaseRecordClassGenerated(TopLevelClass topLevelClass, IntrospectedTable introspectedTable) {
    List<IntrospectedColumn> columns;
    if (introspectedTable.getRules().generateRecordWithBLOBsClass()) {
      columns = introspectedTable.getNonBLOBColumns();
    } else {
      columns = introspectedTable.getAllColumns();
    }

    generateEquals(topLevelClass, columns, introspectedTable);
    generateHashCode(topLevelClass, columns, introspectedTable);

    return true;
  }

  @Override
  public boolean modelPrimaryKeyClassGenerated(TopLevelClass topLevelClass, IntrospectedTable introspectedTable) {
    generateEquals(topLevelClass, introspectedTable.getPrimaryKeyColumns(), introspectedTable);
    generateHashCode(topLevelClass, introspectedTable.getPrimaryKeyColumns(), introspectedTable);

    return true;
  }

  @Override
  public boolean modelRecordWithBLOBsClassGenerated(TopLevelClass topLevelClass, IntrospectedTable introspectedTable) {
    generateEquals(topLevelClass, introspectedTable.getAllColumns(), introspectedTable);
    generateHashCode(topLevelClass, introspectedTable.getAllColumns(), introspectedTable);

    return true;
  }

  /**
   * Generates an <tt>equals</tt> method that does a comparison of all fields.
   * <p>
   * The generated <tt>equals</tt> method will be correct unless:
   * <ul>
   * <li>Other fields have been added to the generated classes</li>
   * <li>A <tt>rootClass</tt> is specified that holds state</li>
   * </ul>
   * 
   * @param topLevelClass
   *          the class to which the method will be added
   * @param introspectedColumns
   *          column definitions of this class and any superclass of this class
   * @param introspectedTable
   *          the table corresponding to this class
   */
  protected void generateEquals(TopLevelClass topLevelClass, List<IntrospectedColumn> introspectedColumns,
      IntrospectedTable introspectedTable) {
    Method method = new Method();
    method.setVisibility(JavaVisibility.PUBLIC);
    method.setReturnType(FullyQualifiedJavaType.getBooleanPrimitiveInstance());
    method.setName("equals"); //$NON-NLS-1$
    method.addParameter(new Parameter(FullyQualifiedJavaType.getObjectInstance(), "that")); //$NON-NLS-1$
    if (introspectedTable.isJava5Targeted()) {
      method.addAnnotation("@Override"); //$NON-NLS-1$
    }

    context.getCommentGenerator().addGeneralMethodComment(method, introspectedTable);

    method.addBodyLine("if (this == that) {"); //$NON-NLS-1$
    method.addBodyLine("return true;"); //$NON-NLS-1$
    method.addBodyLine("}"); //$NON-NLS-1$

    method.addBodyLine("if (that == null) {"); //$NON-NLS-1$
    method.addBodyLine("return false;"); //$NON-NLS-1$
    method.addBodyLine("}"); //$NON-NLS-1$

    method.addBodyLine("if (getClass() != that.getClass()) {"); //$NON-NLS-1$
    method.addBodyLine("return false;"); //$NON-NLS-1$
    method.addBodyLine("}"); //$NON-NLS-1$

    StringBuilder sb = new StringBuilder();
    sb.append(topLevelClass.getType().getShortName());
    sb.append(" other = ("); //$NON-NLS-1$
    sb.append(topLevelClass.getType().getShortName());
    sb.append(") that;"); //$NON-NLS-1$
    method.addBodyLine(sb.toString());

    if (useEqualsHashCodeFromRoot && topLevelClass.getSuperClass() != null) {
      method.addBodyLine("if (!super.equals(other)) {"); //$NON-NLS-1$
      method.addBodyLine("return false;"); //$NON-NLS-1$
      method.addBodyLine("}"); //$NON-NLS-1$
    }

    boolean first = true;
    Iterator<IntrospectedColumn> iter = introspectedColumns.iterator();
    while (iter.hasNext()) {
      IntrospectedColumn introspectedColumn = iter.next();

      sb.setLength(0);

      if (first) {
        sb.append("return ("); //$NON-NLS-1$
        first = false;
      } else {
        OutputUtilities.javaIndent(sb, 1);
        sb.append("&& ("); //$NON-NLS-1$
      }

      String getterMethod = getGetterMethodName(introspectedColumn.getJavaProperty(),
          introspectedColumn.getFullyQualifiedJavaType());

      if (introspectedColumn.getFullyQualifiedJavaType().isPrimitive()) {
        sb.append("this."); //$NON-NLS-1$
        sb.append(getterMethod);
        sb.append("() == "); //$NON-NLS-1$
        sb.append("other."); //$NON-NLS-1$
        sb.append(getterMethod);
        sb.append("())"); //$NON-NLS-1$
      } else if (introspectedColumn.getFullyQualifiedJavaType().isArray()) {
        topLevelClass.addImportedType("java.util.Arrays"); //$NON-NLS-1$
        sb.append("Arrays.equals(this."); //$NON-NLS-1$
        sb.append(getterMethod);
        sb.append("(), "); //$NON-NLS-1$
        sb.append("other."); //$NON-NLS-1$
        sb.append(getterMethod);
        sb.append("()))"); //$NON-NLS-1$
      } else {
        sb.append("this."); //$NON-NLS-1$
        sb.append(getterMethod);
        sb.append("() == null ? other."); //$NON-NLS-1$
        sb.append(getterMethod);
        sb.append("() == null : this."); //$NON-NLS-1$
        sb.append(getterMethod);
        sb.append("().equals(other."); //$NON-NLS-1$
        sb.append(getterMethod);
        sb.append("()))"); //$NON-NLS-1$
      }

      if (!iter.hasNext()) {
        sb.append(';');
      }

      method.addBodyLine(sb.toString());
    }

    topLevelClass.addMethod(method);
  }

  /**
   * Generates a <tt>hashCode</tt> method that includes all fields.
   * <p>
   * Note that this implementation is based on the eclipse foundation hashCode generator.
   * 
   * @param topLevelClass
   *          the class to which the method will be added
   * @param introspectedColumns
   *          column definitions of this class and any superclass of this class
   * @param introspectedTable
   *          the table corresponding to this class
   */
  protected void generateHashCode(TopLevelClass topLevelClass, List<IntrospectedColumn> introspectedColumns,
      IntrospectedTable introspectedTable) {
    Method method = new Method();
    method.setVisibility(JavaVisibility.PUBLIC);
    method.setReturnType(FullyQualifiedJavaType.getIntInstance());
    method.setName("hashCode"); //$NON-NLS-1$
    if (introspectedTable.isJava5Targeted()) {
      method.addAnnotation("@Override"); //$NON-NLS-1$
    }

    context.getCommentGenerator().addGeneralMethodComment(method, introspectedTable);

    method.addBodyLine("final int prime = 31;"); //$NON-NLS-1$
    method.addBodyLine("int result = 1;"); //$NON-NLS-1$

    if (useEqualsHashCodeFromRoot && topLevelClass.getSuperClass() != null) {
      method.addBodyLine("result = prime * result + super.hashCode();"); //$NON-NLS-1$
    }

    StringBuilder sb = new StringBuilder();
    boolean hasTemp = false;
    Iterator<IntrospectedColumn> iter = introspectedColumns.iterator();
    while (iter.hasNext()) {
      IntrospectedColumn introspectedColumn = iter.next();

      FullyQualifiedJavaType fqjt = introspectedColumn.getFullyQualifiedJavaType();

      String getterMethod = getGetterMethodName(introspectedColumn.getJavaProperty(), fqjt);

      sb.setLength(0);
      if (fqjt.isPrimitive()) {
        if ("boolean".equals(fqjt.getFullyQualifiedName())) { //$NON-NLS-1$
          sb.append("result = prime * result + ("); //$NON-NLS-1$
          sb.append(getterMethod);
          sb.append("() ? 1231 : 1237);"); //$NON-NLS-1$
          method.addBodyLine(sb.toString());
        } else if ("byte".equals(fqjt.getFullyQualifiedName())) { //$NON-NLS-1$
          sb.append("result = prime * result + "); //$NON-NLS-1$
          sb.append(getterMethod);
          sb.append("();"); //$NON-NLS-1$
          method.addBodyLine(sb.toString());
        } else if ("char".equals(fqjt.getFullyQualifiedName())) { //$NON-NLS-1$
          sb.append("result = prime * result + "); //$NON-NLS-1$
          sb.append(getterMethod);
          sb.append("();"); //$NON-NLS-1$
          method.addBodyLine(sb.toString());
        } else if ("double".equals(fqjt.getFullyQualifiedName())) { //$NON-NLS-1$
          if (!hasTemp) {
            method.addBodyLine("long temp;"); //$NON-NLS-1$
            hasTemp = true;
          }
          sb.append("temp = Double.doubleToLongBits("); //$NON-NLS-1$
          sb.append(getterMethod);
          sb.append("());"); //$NON-NLS-1$
          method.addBodyLine(sb.toString());
          method.addBodyLine("result = prime * result + (int) (temp ^ (temp >>> 32));"); //$NON-NLS-1$
        } else if ("float".equals(fqjt.getFullyQualifiedName())) { //$NON-NLS-1$
          sb.append("result = prime * result + Float.floatToIntBits("); //$NON-NLS-1$
          sb.append(getterMethod);
          sb.append("());"); //$NON-NLS-1$
          method.addBodyLine(sb.toString());
        } else if ("int".equals(fqjt.getFullyQualifiedName())) { //$NON-NLS-1$
          sb.append("result = prime * result + "); //$NON-NLS-1$
          sb.append(getterMethod);
          sb.append("();"); //$NON-NLS-1$
          method.addBodyLine(sb.toString());
        } else if ("long".equals(fqjt.getFullyQualifiedName())) { //$NON-NLS-1$
          sb.append("result = prime * result + (int) ("); //$NON-NLS-1$
          sb.append(getterMethod);
          sb.append("() ^ ("); //$NON-NLS-1$
          sb.append(getterMethod);
          sb.append("() >>> 32));"); //$NON-NLS-1$
          method.addBodyLine(sb.toString());
        } else if ("short".equals(fqjt.getFullyQualifiedName())) { //$NON-NLS-1$
          sb.append("result = prime * result + "); //$NON-NLS-1$
          sb.append(getterMethod);
          sb.append("();"); //$NON-NLS-1$
          method.addBodyLine(sb.toString());
        } else {
          // should never happen
          continue;
        }
      } else if (fqjt.isArray()) {
        // Arrays is already imported by the generateEquals method, we don't need
        // to do it again
        sb.append("result = prime * result + (Arrays.hashCode("); //$NON-NLS-1$
        sb.append(getterMethod);
        sb.append("()));"); //$NON-NLS-1$
        method.addBodyLine(sb.toString());
      } else {
        sb.append("result = prime * result + (("); //$NON-NLS-1$
        sb.append(getterMethod);
        sb.append("() == null) ? 0 : "); //$NON-NLS-1$
        sb.append(getterMethod);
        sb.append("().hashCode());"); //$NON-NLS-1$
        method.addBodyLine(sb.toString());
      }
    }

    method.addBodyLine("return result;"); //$NON-NLS-1$

    topLevelClass.addMethod(method);
  }
}
